diff options
| author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2008-03-05 16:13:04 +0000 |
|---|---|---|
| committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2008-03-05 16:13:04 +0000 |
| commit | 7cf3d2829371ab6a0a98f7c504942d290ab81c79 (patch) | |
| tree | f34248a3bddd1b90c01b24609c94f0ff59cae43d /gcc | |
| parent | 2349cd3e43379cd107ab0248ed10ff5c3352e0eb (diff) | |
| download | gcc-7cf3d2829371ab6a0a98f7c504942d290ab81c79.tar.gz | |
2008-03-05 Richard Guenther <rguenther@suse.de>
PR tree-optimization/35472
* tree-ssa-dse.c (dse_optimize_stmt): Do not delete a store
whose single use_stmt has a overlapping set of loaded and
stored symbols as that use_stmt might be a noop assignment then.
* gcc.c-torture/execute/pr35472.c: New testcase.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@132899 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 7 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.c-torture/execute/pr35472.c | 22 | ||||
| -rw-r--r-- | gcc/tree-ssa-dse.c | 33 |
4 files changed, 50 insertions, 17 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index fe414641c34..a179d15064c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,10 @@ +2008-03-05 Richard Guenther <rguenther@suse.de> + + PR tree-optimization/35472 + * tree-ssa-dse.c (dse_optimize_stmt): Do not delete a store + whose single use_stmt has a overlapping set of loaded and + stored symbols as that use_stmt might be a noop assignment then. + 2008-03-05 Joel Sherrill <joel.sherrill@oarcorp.com> * gthr-rtems.h: Implement __gthread_mutex_destroy. diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 8341b280545..98246904330 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2008-03-05 Richard Guenther <rguenther@suse.de> + + PR tree-optimization/35472 + * gcc.c-torture/execute/pr35472.c: New testcase. + 2007-03-05 Gabor Loki <loki@gcc.gnu.org> PR 33009 diff --git a/gcc/testsuite/gcc.c-torture/execute/pr35472.c b/gcc/testsuite/gcc.c-torture/execute/pr35472.c new file mode 100644 index 00000000000..c8678e268c9 --- /dev/null +++ b/gcc/testsuite/gcc.c-torture/execute/pr35472.c @@ -0,0 +1,22 @@ +extern void abort (void); +extern void *memset (void *s, int c, __SIZE_TYPE__ n); +struct S { int i[16]; }; +struct S *p; +void __attribute__((noinline)) +foo(struct S *a, struct S *b) { a->i[0] = -1; p = b; } +void test (void) +{ + struct S a, b; + memset (&a.i[0], '\0', sizeof (a.i)); + memset (&b.i[0], '\0', sizeof (b.i)); + foo (&a, &b); + *p = a; + *p = b; + if (b.i[0] != -1) + abort (); +} +int main() +{ + test(); + return 0; +} diff --git a/gcc/tree-ssa-dse.c b/gcc/tree-ssa-dse.c index 3e0f04be124..f2ec9a505c7 100644 --- a/gcc/tree-ssa-dse.c +++ b/gcc/tree-ssa-dse.c @@ -470,24 +470,23 @@ dse_optimize_stmt (struct dom_walk_data *walk_data, vuse_vec_p vv; tree stmt_lhs; - if (LOADED_SYMS (use_stmt)) + /* If use_stmt is or might be a nop assignment, e.g. for + struct { ... } S a, b, *p; ... + b = a; b = b; + or + b = a; b = *p; where p might be &b, + or + *p = a; *p = b; where p might be &b, + or + *p = *u; *p = *v; where p might be v, then USE_STMT + acts as a use as well as definition, so store in STMT + is not dead. */ + if (LOADED_SYMS (use_stmt) + && bitmap_intersect_p (LOADED_SYMS (use_stmt), + STORED_SYMS (use_stmt))) { - tree use_base - = get_base_address (GIMPLE_STMT_OPERAND (use_stmt, 0)); - /* If use_stmt is or might be a nop assignment, e.g. for - struct { ... } S a, b, *p; ... - b = a; b = b; - or - b = a; b = *p; where p might be &b, then USE_STMT - acts as a use as well as definition, so store in STMT - is not dead. */ - if (TREE_CODE (use_base) == VAR_DECL - && bitmap_bit_p (LOADED_SYMS (use_stmt), - DECL_UID (use_base))) - { - record_voperand_set (dse_gd->stores, &bd->stores, ann->uid); - return; - } + record_voperand_set (dse_gd->stores, &bd->stores, ann->uid); + return; } if (dump_file && (dump_flags & TDF_DETAILS)) |